The methods of suspending at least one weighting agent in a drilling fluid include synthesizing carbon nanotubes via chemical vapor deposition on iron oxide catalyst nanoparticles to form a quantity of nanoparticles. Individual nanoparticles of the iron oxide catalyst nanoparticles include a transition metal disposed on iron oxide. The embodiments further include adding a quantity of nanoparticles to the drilling fluid which results in an amount of carbon nanotubes dispersed within the drilling fluid. The dispersion of the quantity of nanoparticles increases the value of at least one of a Newtonian viscosity, a yield point, a plastic viscosity, and a density of the drilling fluid with the dispersed nanoparticles versus a similar or equivalent drilling fluid without the nanoparticle dispersion. The method may further include adding at least one weighting agent which will become suspended in the drilling fluid.

The present invention relates to carbon nanotubes that are excellent in dispersibility and a process for producing the carbon nanotubes. The carbon nanotubes according to the present invention each comprise a wall that comprises a parallel portion and a narrowed portion having a tube outer diameter that is not more than 90% of a tube outer diameter of the parallel portion. Thus, the carbon nanotubes are readily dispersible owing to a high abundance ratio of easily-breaking portions.

The present invention relates to carbon nanotubes that are excellent in dispersibility and a process for producing the carbon nanotubes. The carbon nanotubes according to the present invention each comprise a wall that comprises a parallel portion and a narrowed portion having a tube outer diameter that is not more than 90% of a tube outer diameter of the parallel portion. Thus, the carbon nanotubes are readily dispersible owing to a high abundance ratio of easily-breaking portions.

This invention relates to a process and an apparatus for synthesizing multiwall carbon nanotubes from high molecular polymeric wastes. The process comprises using induction heating in combination with catalytic chemical vapour deposition (CVD) with an array of catalytic materials to synthesize high value carbon nanotubes with better yield and purity from high molecular polymeric wastes.

This invention relates to a process and an apparatus for synthesizing multiwall carbon nanotubes from high molecular polymeric wastes. The process comprises using induction heating in combination with catalytic chemical vapour deposition (CVD) with an array of catalytic materials to synthesize high value carbon nanotubes with better yield and purity from high molecular polymeric wastes.

A carbon nanotube aggregate according to one embodiment of the present invention includes a plurality of carbon nanotubes, in which: the carbon nanotubes each have a plurality of walls; a distribution width of a wall number distribution of the carbon nanotubes is 10 walls or more; a relative frequency of a mode of the wall number distribution is 25% or less; and a length of each of the carbon nanotubes is more than 10 μm. A carbon nanotube aggregate according to another embodiment of the present invention includes a plurality of carbon nanotubes, in which: the carbon nanotubes each have a plurality of walls; a mode of a wall number distribution of the carbon nanotubes is present at a wall number of 10 or less; a relative frequency of the mode is 30% or more; and a length of each of the carbon nanotubes is more than 10 μm.

A method of reducing a gaseous carbon oxide includes reacting a carbon oxide with a gaseous reducing agent in the presence of a non-ferrous catalyst. The reaction proceeds under conditions adapted to produce solid carbon of various allotropes and morphologies, the selective formation of which can be controlled by means of controlling reaction gas composition and reaction conditions including temperature and pressure. A method for utilizing a non-ferrous catalyst in a reactor includes placing the catalyst in a suitable reactor and flowing reaction gases comprising a carbon oxide with at least one gaseous reducing agent through the reactor where, in the presence of the catalyst, at least a portion of the carbon in the carbon oxide is converted to solid carbon and a tail gas mixture containing water vapor.

A method of forming an array of aligned, uniform-length carbon nanotubes on a planar surface of a substrate employing a composite catalyst layer of iron and cobalt. The carbon nanotubes have visible length and are useful for producing spun threads of carbon nanotubes having improved spinability and mechanical and electrical properties.

A method of forming an array of aligned, uniform-length carbon nanotubes on a planar surface of a substrate employing a composite catalyst layer of iron and cobalt. The carbon nanotubes have visible length and are useful for producing spun threads of carbon nanotubes having improved spinability and mechanical and electrical properties.

A mechanically robust, binder-free, inexpensive target for laser synthesis of carbon nanotubes and a method for making same, comprising the steps of mixing prismatic edge natural flake graphite with a metal powder catalyst and pressing the graphite and metal powder mixture into a mold having a desired target shape.